public class Circle {
    double x;  // 圆心坐标
    double y;
    double r;  // 圆的半径
    // 对圆的属性进行设置和获取
    public double getX() {
        return x;
    }

    public void setX(double x) {
        this.x = x;
    }
    public double getY(){
        return y;
    }
    public void setY(double y){
        this.y = y;
    }
    public double getR(){
        return r;
    }
    public void setR(double r){
        this.r = r;
    }
    // 计算圆的周长的方法
    public double perimeter(){
        double circle_meter = Math.PI*2 *r;
        return circle_meter;
    }
    // 计算圆的面积
    public double area(){
        double circle_area = Math.PI*Math.pow(r,2);
        return circle_area;
    }
}
